Sorry to bother you all. Two questions came up from our side:
-should we include volcano emission in the base case? For the NA simulation it is stated explicitly that they should not be included, for the European case nothing is mentioned.
-For which wave lengths should we calculate AOD? Both (470, 550 en 650) and (470, 555 en 675 ) are mentioned.

Regarding AOD: You are right that there is an inconsistency in the overarching documents in terms of wavelengths to be saved by the modelers and the wavelengths to be delivered to JRC.
I’d recommend to output AOD at 470,555 and 675 nm or to follow the recommendations on the wiki if you’d like to store AOD for the wavelength bands of your model. Differences will be small in any case, I think.

Each model should write out the AOD it computes internally. For COSMO-ART, for example, we are writing out the 3D distribution of optical depths per model layer but only for 555 nm which we assume to be in the center of our broad wavelength band. We can thus not compute any Angstrom exponent from this output but at least we can compare with MODIS and AERONET at that wavelength. With 532 nm the Calipso Lidar is also close enough.

At a later stage and for the purpose of understanding differences between models we may also compute AOD from our 3D bulk aerosol model output using FLEXAOD (http://wiki.seas.harvard.edu/geos-chem/index.php/FlexAOD) as proposed by Gabriele Curci. However, for the moment we should not use FLEXAOD but rather save our internally computed AODs.